de normanville



S. A. DE NORMANVILLE.

SPRAY GUARD FOR TELESCOPES.

APPLICATION FILED MAR.2I= 191a.

Patented May 27, 1919.

4 SHEETS-SHEET i.

fizacvzfar S. A. DE NORMANVILLE.

SPRAY GUARD FOR TELESCOPES.

APPLICATION FILED MAR. 21. 1918.

1,304,548. Patented May 27 1919.

4 SHEETS-SHEET 2.

fizz/swim S. A. DE NORMANVILLE.

SPRAY GUARD FOR TELESCOPES.

APPLICATION FILED MAR-21.1918.

1,304,548. Patented May 27, 1919.

4 SHEETS-SHEET 3- S. A. DE NORMANVILLE.

SPRAY GUARD FOR TELESCOPES APPLICATION FILED MAR. 21. 1918.

1,304,548. 1 Patented May 27, 1919 4 SHEETS-SHEET 4.

SAMUEL AUGUSTINE NORMANVILLE, OF LONDON, ENGJJAND.

SPRAY-GUARD FOR TELESCOPES.

Specification of Letters Ifatent.

Application filed March 21, 1918. Serial No. 223,700.

T 0 all whom it may concern:

Be it known that I, SAMUEL AUGUSTINE Dr. NORMANVILLE, a subject of the King of Great Britain, residing at London, England, have invented certain new and useful Improvements in Spray-Guards for Telescopes, of which'the following is a specification.

This invention relates to telescopes and particularly telescopes (direct or periscopic) used for sighting guns, the object being to avoid the constant cleaning of the object glass usually necessary in order to remove moisture deposited by spray or rain;

The invention consists in the provision of a cover for the front portion of a telescope, preferably out of contact with it and so mounted from the same carrier as to participate in its movements of elevation and deviation, the front of such cover being closed in by a centrifugal spray guard in the form of a rotating transparent disk so carried and driven as to leave the field of view of the telescope entirely unobstructed.

In the accompanying drawingsFigure 1 is a sectional side elevation illustrating one form of the invention, in which one form of air motor is used to rotate the spray guard,

Figs. 2 and 3 being front and rear elevations corresponding thereto.

Fig. 4 is a side sectional elevation and Fig. 5 a front elevation illustrating another form of air motor,

Fig. 6 being a frontelevation of a detail connected therewith.

Fig. 7 is an elevation illustrating another "form of the invention with the aid of an electric motor, part of the protective casing being shown broken away.

,-' Fig. 8 is a detail section'of part of the apparatus shown in Fig. 7.

Fig. 9 is a side elevation showing the application of the .invention to the head of a periscopic sighting telescope of usual form. Fig. 10 is a side elevation showing the application of the invention to the usual sighting telescope of a gun.

In one form of the invention, for example suitable for use with a telescope for use on a naval gun, a tube 1, Figs. 1 to 3, is mounted on the support carrying the telescope so as to surround the front portion of the latter and move co-axially with it. The tube 1, forms a cover over that end of the telescope and is of sufiicient length and diameter to triangular cross section.

allow of the usual adjustments of the telescope and to avoid actual contact therewith.

Patented May 27, 1919.

A flanged sleeve or socket 2 is screwed into the outer end of the tube 1 and carries a ballbearlng 3 on which an outer ring or cap 4 is adapted to rotate freely. The cap 4 has a flange 5 adapted to rotate out of contact with the locking ring 6 of the bearing 3. The inner edge of the cap 4 is screwed to a ring 6 preferably provided with grooves 7 holding oil and forming labyrinth packing to prevent moisture entering the ball-bearing.

The cap 4 is recessed in front to receive a glass disk 8, and is screw-threaded to receive a clamping ring 9 for the disk.

The ring 6' is adapted to form the driving member for the disk. In other words the disk is driven peripherally and not from the center as hitherto adopted in the case of look-out visual screens where a certain amount of obstruction in the center of the disk is immaterial.

In the case of a telescope of this class, however, the central portion of the object glass must be absolutely clear of any obstruction. It is also highly desirable that the driving means should not set up any vibration and should be as light and compact as possible. For these reasons a compressed air motor may be employed to rotate the disk. A very simple motor is provided by forming the ring 6 as a vane wheel and pro pelling it by compressed air from one or more jets or nozzles 10 which can be carried conveniently on a bracket 11 or brackets secured to the support carrying the guard tube 1.

In a lighter form of apparatus the air motor for rotating the glass disk 8, may be constructed as shown in Figs. 4 to 6. This form also dispenses with ball bearings as the vane wheel, when rotating at a proper speed, floats as it were, on an annular film of air.

The disk 8 is shown clamped between two rings 12, screwed into a ring 13 of vulcanite or other light material and of substantially The ring 13 is freely housed within a. V ring 14 carriedby brackets (not shown) from the tube 1. The inner faces of the ring 14 are provided with ridges or facets 15 against which thering 13 can rest. The inner faces are thus divided into a number of recesses 16 into which air from an air chest 17 can enter through holes 18 some or all of which may be inclined so that the air may impinge at an angle on the ring 13.

In Figs. 4 and 5 the ring 13 is shown at 5 rest supported on the lower facets 15. In

this position the lower recesses 16 are practically closed in by the ring 13 while the upper recesses are more open to the outer air. When therefore compressed air is admitted to the air chest 17 and passes through the holes 18 a superior pressure is at first developed in the lower recesses 16 and the ring 13 is lifted until a balance of pressures between the lower and upper recesses 16 is approximated and the ring and the disk are supported and lubricated by an annulus of air thereby forming an air bearing. At the same time the air escaping between the rings '13 and 14 and impinging on the vanes 19,

causes the ring 13 to rotate rap-idly. The ring 13 thereby finds a floating position in which it rotates as it were on a film of air with extremely little friction.

Thereafter any displacement, either in the direction of the plane of the ring 13, or in a direction along its axis of rotation is accompanied by a development of excess air pressure in the recess or recesses on the side to ward which displacement takes place due to partial closing up of the clearance between the ring 13 and the facets 15. A corresponding reduction of air pressure, due to increased clearance takes place on the opposite side. Displacement is thus resisted and if it takes place due say to a heavy gust of Wind or impact of spray, is quickly corrected.

The V ring 14 may be made in two parts as shown, separated by packing 21, the thickness of which may be varied to allow the clearance between the rings 13 and 14 to be accurately adjusted.

A form of the invention above described with reference to Figs. 4 to 6 is shown applied to the head of a periscopic sighting telescope 30 in Fig. 9. The air chest 17 is secured by brackets 31 to a tubular cover 32 secured to the head of the periscopic telescope 30 in front of the lens aperture 33.

The same form of the invention is shown applied to a gun sighting arm 34 in Fig. 10. The cover or tube 1 and a bracket 35 for the telescope 36 are secured to the arm 34 which is pivoted at 38 and is of usual construction adopted in the art so that it needs no further description here.

In another mode of carrying out the invention an electric motor is used to rotate the glass disk 8. For example as somewhat diagrammatically shown in Figs. 7 and 8, a ring armature 22 of a direct current motor is mounted on an extension of the ring 6'. Field magnets 23 are carried by the tube 1. Any suitable winding and form of commutator may be used, the commutator 24 in the example shown being mounted on the exnaoaaae tension of the ring 6' and carbon brushes 25 being carried by holders 26 mounted on the field magnets. The whole device is preferably inclosed in a. suitable protective casing 27.

I claim 1. The combination of a telescope and its support, of a rotary transparent disk in the field of vision of the telescope, and a motor for rapidly rotating said disk, said disk and motor being mounted upon such support to partake of the movement of the telescope.

2. A centrifugal spray or like guard for a telescope comprising a cover for the front of said telescope, a rotary transparent disk closing the front of said cover, and a motor for rotating said transparent disk, said m0- tor being carried. by said cover and being situated outside the field of view of said telescope, substantially as hereinbefore set forth.

3. The combination with a telescope support and a telescope movably mounted thereon, of a cover for the front of the telesco e, a rotary transparent disk inclosing the ront of the cover, said cover and disk being coaxial with the telescope, and a motor for rotating said disk, the cover, disk and motor being mounted upon the support to move with the telescope.

4. A centrifugal spray or like guard for a telescope comprising a cover for the front of the telescope, a rotary transparent disk closing the front of said cover, and an air motor for rotating said disk whereby the field of view of the telescope is entirely unobstructed, said air motorcomprising a vane wheel adapted to find a free position in a state of balance under the Pressure of the air used to rotate the vane wheel, substantially as hereinbefore set forth.

5. A centrifugal sprayor like guard for a telescope comprising a cover for the front of the telescope, a rotary transparent disk closing the front of said cover, and an air motor for rotating said disk whereby the field of view of the telescope is entirely unobstructed, said air motor comprisin a vane wheel carrying said transparent dis an air chest surrounding said vane wheel and having means for directing air on to said vane wheel adapted to permit of said vane wheel rotating freely and also assuming a free position in a plane at right angles to its axis in a state of balance, substantially as hereinbefore set forth.

6. A centrifugal spray or like guard for a telescope comprising a cover for the front of the telescope, a rotary transparent disk closing the front of said cover, and an air -motor for rotating said disk whereby the vane wheel having an outer ring of triangular cross section, an air chest surroundin said vane wheel and having a housing 0 corresponding form for said ring, said housin having recesses in its faces opposing said ring, and holes communicating with the interior of said ail-chest and said recesses for directing air onto said ring and thence on to the' l vane Wheel, the vane wheel'being free relatively to the air chest so that when stationary it rests on the lower part of the aforesaid housing and substantially closes the lower of the recesses therein, substantially as and for the purpose hereinbefore set forth..

7. A centrifugal spray or like guard for a telescope comprising a cover for the front of the telescope, a rotary transparent disk closing the front of said cover, and an air motor for rotating said disk whereb the field of view of the telescope is entire y unobstructed, said motor comprising a vane Wheel carrymg said transparent disk, a housing surrounding said vane wheel, said vane wheel being free relatively to said housing and means for directing 'air against said vane wheel to rotate the same and to form an air bearing between said Wheel and housing.

8. A centrifugal spray guard for the telescope, comprising a cover for the telescope which" is out of contact therewith to avoid transmission of vibration from the cover to the telescope, a common support for the telescope and cover adapting the cover to participate in-the movements of sald telescope in elevation and deviation, a rotary SAMUEL AUGUSTINE DE NORMANVILLE. I

Witnesses:

ANNE MASSOA MARTIN, H. MATHYS. 

